What is Chemistry? - Explained by Group 1 Co-editor: Nathaniel Gullishaw Members: Michael Clarke
Section 1.1
Matter is anything that has mass and occupies space. It can be visible or invisible. Chemistry is the study of the composition of matter and the changes that matter undergoes. Chemistry applies to all aspects of life and most natural events because all living and nonliving things are made of matter.
Areas of Study
The scope of chemistry is vast, and there are traditionally 5 areas of study. These are
Organic Chemistry - Defined commonly as the study of all chemicals containing carbon. This encompasses anything that is alive.
Inorganic Chemistry - The opposite of Organic Chemistry, Inorganic Chemistry is the study of all chemicals that do not contain carbon.
Biochemistry - Biochemistry is defined as the study of processes that take place in an organism. This includes humans.
Analytical Chemistry - The study of the composition of matter. An example would be measuring lead levels in water.
Physical Chemistry - Defined as the area that deals with the mechanism, rate, and energy transfer that occurs when matter undergoes a change.
Pure and Applied Chemistry
Pure Chemistry is the study of chemistry for the sake of knowledge.Applied Chemistry is chemistry with a specific goal in mind. Sometimes, applied chemistry and pure chemistry can link to unexpectedly form an application. Such examples are: Nylon Aspirin Technology
Technology is how society provides its members with things needed or desired.
Why Study Chemistry? Chemistry can impact all aspects of your life. Chemistry can be useful in explaining the natural world, preparing people for career opportunities, and producing informed citizens. Explaining the Natural World Chemistry can help you understand how things work. For example, chemistry can explain numerous aspects of food preparation. Preparing For a Career Being a chemist can be rewarding. Many careers involve chemistry, even though they do not necessarily include the word "chemist" in their title. People such as firefighters, reporters, and photographers all use chemistry at work. Being an Informed Citizen Industry, private foundations, and the federal government provide funds for research involving science. Many areas of research sometimes compete for funds. Some argue in favor of using funds for space exploration through programs such as NASA, while others support causes such as cancer research. Citizens will need to make choices that will determine the future development of technology. You may make decisions through elected representatives, at public hearings, or through petitions. Your knowledge of chemistry can help you make an informed decision and take appropriate action.
Chemistry Far and Wide - Explained by Group 2 Co-editor: Christopher Delude Members: Kendall Lavin-Parsons
Section 1.2
Chemists try to design new materials to better fit specific needs of people. They often find inspiration for new designs in nature. They look at both the worlds of: Macroscopic-the world of objects that are large enough to see with the naked eye (no help from microscopes, magnifying devices, etc) Microscopic- the view of objects only able to be seen under magnification
With the population growth and increase in industrialization, the need for energy is much higher. Chemists play an important role in finding ways to conserve, store, and produce energy.
Conservation Insulation is the most common form of conservation of energy. It maximizes the use of our heating and cooling that we use in daily situations (refrigeration, stoves, homes, etc). Chemists try to create new materials which insulate better and conserve our energy
Production Burning fossil fuels such as coal, petroleum, and natural gas is our major source of energy. Fossil fuels are a limited recourse, and chemists are trying to find energy sources that can be created easily. One plausible alternative is biodiesel. Biodiesel is energy made from plants, such as soy beans. Biodiesel is also better than fossil fuels (not only because it is renewable), but also because when used it does not release harmful gas for the environment. Storage The most common storage for energy is in batteries. Various sizes, shapes, and functions are available for them (including rechargeable) to fit the needs of differing functions.
<http://www.foxnews.com/story/0,2933,516738,00.html> Biotechnology has been the most important result from chemistry. It applies science to the production ofbiological products. It supplies new medicines, equipment, and technology for doctors to use to treat their patients.
Medicines There are over 2,000 prescription drugs used to treat a variety of conditions. There are many other “over the counter” drugs such as aspirin or antacids which do not require prescriptions. Chemists work with biologists and doctors to help create these new medicines. Materials Chemists can create new materials to replace parts of the body which are not functioning. Plastic tubes can replace diseased arteries. Artificial knees and hips can replace worn out joints which cause a patient pain.
Agriculture The worlds population is increasing - while the amount of space available to grow crops is decreasing, there fore we all must ensure to make this space as productive as possible.
Productivity
One method of measuring productivity is is to see how much edible food is grown per a unit of land.
Factors that decrease productivity; bad soil, lack of water, weeds, plant diseases, pests.
Chemists can help increase productivity by testing the soil and using biochemistry to develop plants best capable of growing in bad weather.
Chemists help to conserve water also.
Crop Protection
Instead of using non specific chemicals that were actually hurting the crops they now use chemicals that are specifically tested to only kill the bad pests.
Some chemicals that are produced by insects can be used and manipulated to get rid pf bad insects.
EX: female insects release a cchemical used to attract male insects and this chemical is proven to reduse pinworms.
Enviornment
Technology has some bad consequences including pollutants - material found in air, water, or soil that is harmful to humans and other organisms
Identify Pollutants
Lead is a pollutant.
In the Roman empire lead was used in the pipes to store water and wine which might have lead to brain damage and ultimately the fall of the empire.
It wasnt until after the mid 1900s that lead was stopped being used in common and dangerous products because studies taken in 1971 showed that even a very low level of lead in human blood is dangerous especially to young children.
Prevent Pollution
Use of lead in house paint was banned in 1978.
Use of lead in gasoline and public water supply systems was banned in 1986.
Prevention methods include; testing childrens blood, rules on house sales to families with children, and public awareness about how dangerous lead is.
The Universe
Methods used to study the Earth can also be used to study other things in the Universe.
The compostition of stars was studied by the light they transmitted to Earth.
Pierre Janssen discovered Helium on the suns surface in 1868.
William Ramsay discovered helium on Earth in 1895.
In order to study other planets and things that dont emit light scientist use matter brought back to Earth from there.
Studies show that the moon might have once been covered in lava.
The vehicle called the Opportunity discovered that Mars was once covered in water.
Thinking like a Scientist - Explained by Group 3 Co-editor: Sean Doherty Members: Monika Maczuga Abby Williams
Section 1.3
Alchemy - The word chemistry derives from the word alchemy - Alchemy flourished in China and India as early as 400 B.C. Eventually, the Arabs brought the study to Spain. From there, it spread through Europe like wildfire.- Alchemy has a practical side and a mystical side (the best of both worlds) Practical Alchemy primarily focuses on developing techniques for working with metals, glass, dyes, etc. Mystical Alchemy focuses on concepts such as perfection. Example: Since gold was valued as a perfect metal, alchemists were always seaching for ways to transform other less illustrious metals, such as lead, into gold. Outcome: None successfully completed the goal of a "new gold." - Alchemists were also brilliant crafters of tools and techniques for working with various chemicas. We can thank them for allowing us to seperate and purify chemicals.
Examples of tools we use today: flasks, tongs, funnels, and the mortar (bowl shaped) and the pistle which is used as a grinder. An Experiemental Approach to Science - 1500s in Europe = shift from alchemy to science. - 1600s in Britain = flourishing sciences under its supporter, King Charles II. Royal Society of London for the Promotion of Natural Knowledge: 1. Scientists met to discuss scientific topics and conduct experiments. 2. The goal was to encourage and promote scientists to base their conclusions about the natural world on experimental evidence, not on philosophical debates. Antoine Lavoisier!!! - Late 1700s = his famous works took shape (France). - Eventually, his brilliance would help transform chemistry from a science of observation to the science of measurment it is today. Accomplishments: 1. Lavoisier developed an ingeniuos balance which could measure mass to the nearest 0.0005 gram. 2. Settled a long standing debate on how materials burn (oxygen). ~ During his time, the idea excepted was that materials burn because they contain phlogiston, which is released into the air as a material burns. ~ However, scientists had to ignore the fact that metals can gain mass as they burn. Lavoisier knew that there were two main gases in the air- oxygen and nitrogen. ~ He was able to successfully prove that oxygen must be present for a material to burn Maria Anne was Lavoisier's wife and valuable aid. She was artistic allowing for her to make drawings of his experiments and translated scientific papers from English.
Execution: - Lavoisier was a member of a despised royal taxation commission at the time of the French Revolution. - He took the position to finance his scientific work. PROBLEM! - Although he was dedicated to improving the lives of the common people, his association with bitter taxation made him a prime target. - In 1794, he was arrested, found guilty, and beheaded.
The Scientific Method - Scientific tool used for solving problems with a logical, systematic approach. -The method used steps that include making observations,testing hypotheses, anddeveloping theories.
http://sites.google.com/site/msjarrettsite/notes
-Process begins by making an observation - Next a hypothesis is created, or a guess, which you will test to find a result. -These tests usually contain variable factors which can change the results of the test. - Manipulated variables are changed to alter the results. - Responding Variables are observed during the test. - The outcomes of these hypotheses experiments result in theories, or well tested result that stays the same for a broad set of observations. -Theories are then developed into laws, which are proven statements. Collaboration and communication - The use of team work to utilize the skill sets of each person working. -Collaboration- The sharing of results or ideas with other scientists to gain more insight. - Can also result in conflict with amount of workload to credit -Communication- The use of technology to communicate results and ideas to others. (Internet!)
Problem Solving in Chemistry - Explained by Group 4 Co-editor: Andrew Whalen Members: Katie Manis, Freddy Dwyer
Section 1.4
SkillsUsed in Solving Problems -Problem solving is a skill used by people every day - Decisions are made using problem solving skills For example: You are in a supermarket and need to purchase an item. Problem solving and decision making come into play when you choose between a 1 and 2 liter bottle. Sometimes you must decide whether or not to buy a certain item based on ingredients that are in it. You may need to avoid certain ingredients due to an allergy you or a family member posseses. These are examples of problem solving that are used every day. -The skills used to solve a word problem in chemistry are not much different from the scenario listed above. *EFFECTIVE PROBLEM SOLVING ALWAYS INVOLVES DEVELOPING A PLAN AND THEN IMPLEMENTING THAT PLAN*
Solving Conceptual problems:
To solve a conceptual problem you need to identify what is known and what is unknown.
-you need to make a plan for getting from the known to the unknown.
The three step problem solving approach is modified for conceptual problems.
The steps for solving a conceptional problem are analyze and solve.
-when analyzing you identify the relevant concepts. -when solving the problem you apply concepts to the situation.
Measurement and their Uncertainty - Explained by Group 5 Co-editor: Andrew Humphrey Members: Matthew McKeon, Lindsey Trafford
Section 3.1
Using and Expressing Measurement
Measurement is a quantity that has both a number and a unit.
Measurements are fundamental to the experimental sciences. For that reason, it is important to be able to make measurements and to decide whether a measurement is correct.
The units typically used in the sciences are The International System of Measurements (SI).
In Scientific Notation, a given number is written as the product of two numbers: a coefficient and 10 is raised to a power. For example the number 602,000,000,000,000,000,000,000 in scientific notation is 6.02 X 10 to the twenty third power. The coefficient in this number is 6.02. In scientific notation, the coefficient is always a number equal to or greater than one and less than ten.
Accuracy, Precision, and Error
Accuracy and Precision
Accuracy is a measure of how close a measurement comes to the actual or true value of whatever is measured.
Precision is a measure of how close a series of measurements are to one another.
To evaluate the accuracy of a measurement, the measured value must be compared to the correct value. To evaluate the precision of a measurement of a measurement, you must compare the values of two or more repeated measurements.
Determining Error
Accepted value is the correct value based on reliable refrences .
Experimental value is the value measured in the lab.
The difference between the accepted value and the experimental value is the error.
Error can be positive or negative depending on whether the experimental value is greater than or less than the accepted value.
The percent error is the absolute value of the error divided by the accepted value, multiplied by 100%.
Using the absolute value of the error means that the percent error will always be a positive value.
Significant figures in measurements
Significant figures in a measurement includes all of the digits that are already known and the last digit which is estimated.
Calculated numbers often depend on the number of significant figures in a value used in a calculation.
- because calculated numbers depend so much on the significant figures the correct number of significant figuresmust always be reported.
The instruments used for measurement differ in significant figures and the amount of exact information they can provide.
- the calculations may all depend on the calibration of the instrument. Rules for determining whether a digit in a measurement is a significant figure:
Every number that is not zero is assumed to be a significant figure (e.g. 24.7meters, 0.734 meter, and 714 meter).
When a zero appears between two non-zero digits it is a significant figure (e.g. 7003meter, 40.79 meter, and 1.503 meter).
Zeros in front of non-zero digits (significant figures) are not significant figures. they can be eliminated by using scientific notation (e.g. 0.0071 meter, 0.42 meter, and 0.000099).
Zeros to the left of non-zero digits are significant figures (e.g. 43.00meters, 1.010 meters, and 9.000 meters).
Zeros on the left of a decimal point but to the rightmost of the numbers are not significant figures. they can be put into scientific notation( e.g. 300 meters, 7000meters, and 27, 210 meters).
there are 2 situations in which there is an unlimited number of significant figures. one involves counting and the other includes exactly defined quantities like those within a system of measurement. (e.g. counting 23 people in a class, or 60 min=1 hr, or 100 cm= 1 m)
Significant figures in calculations
When calculating significant figures the solution cannot be more precise than the least precise measurement in the calculation. the calculation must be rounded to make it consistant with the measurements in which it was calculated. (e.g. 7.7 meters by 5.4 meters equals 41.58 meters but the answer can only consist of two significant figures to match the calculated measurements 41.58 meters must be rounded to 42 m2).
Addition and subtraction
The answer to a addition or subtraction calculation should be rounded to the same number of decimal places as the measurments with the least number of decimal place.
The Internal System of Units - Explained by Group 6
Co-editor: Lauren Rossi Members: Patrick Hodge, Kevin Petterson.
Section 3.2
Measuring with SI units international system of units- a revised version of the metric system. It was adopted in 1960. The five base units used by chemists are meter, kilogram, kelvin, second, and mole. Units and Quantities
Units of Length
size is an important property of matter
meter-the basic length or linear measure. All measurements can be measured in meters.
milli- prefix that means 1/1000. millimeter= 1/1000 of a meter
kilo- prefix that mean 1000. kilometer= 1000 meters
Common metric units of length- centimeter, meter, and kilometer.
Units of Volume:
The space occupied by any sample of matter is called its volume.
Scientists commonly use two equivalent units of temperature, the degree Celsius and the kelvin
Celsius scale- sets the freezing point of water at 0degrees and the boiling point of water at 100 degrees.
Named after the Sweedish astronomer Anders Celsius
Uses two readily determined temperatures as reference temperature values
The freezing point of water
The boiling point of water
The distance between the two fixed points is divided into 100 equal intervals, or degrees Celsius
Conversion Problems - Explained by Group 7 Co-editor: Emily Mills Members: Kelsey Persechini, Emily Healy
Section 3.3
Conversion Factors
A quantity of the same amount or length can usually be expressed or measured in several different ways:
1 dollar = 4 quarters = 10 dimes = 20 nickels = 100 pennies OR
1 meter = 10 decimeters = 100 centimeters = 1000 millimeters
A conversion factor is a ratio of equivalent measurements.
Example ratio: 100cm / 1m and 1m / 100cm
Smaller number --> 1 m <-- larger unit
Larger number --> 100 cm <-- smaller unit
Measurement of the numerator = Measurement of the denominator
Conversion factors are useful in solving a problem that a given given measurement must be expressed in another unit.
When a measurement is multiplied by a conversion factor, the numerical value is generally changed, but the actual size of the quantity measured remains the same.
In other words, even though the numbers in the measurement are different, both of the measurements represent the same mass.
Converting Between Units
In chemistry you must express measurement using a different unit than what is given or given in the first place
Converting between metric units is easy to remember
kilo- hecto- deka- [unit] deci- centi- milli-
one memory trick Is “King Henry Doesn't [Usually] Drink Chocolate Milk”
Between every unit is 10^1 with every place it goes up on exponent point 1 kilometer = 10 hectometers = 100 dekameters = 1000 meters = 10 000 decimeters = 100 000 centimeters = 1 000 000 millimeters
If the unit is a gram that the different between a kilogram and a decigram is 104
If you are going up of left of the units than you divide and if you are going down or right you multiply
Example
Express 750 decigrams in gram
Mass= 750dg
1g= 10dg so 750/10 =?
750/10=75
750 decigram= 75 gram
another way to think of it is
If you are going from a kilometer to a centimeter
How many jumps is it from "kilo-" to "centi-"? Five, to the right. So I move the decimal point five places to the right, filling in the extra space with zeroes: 12.54 km = 1 254 000 cm
If you are going from a milliliter to hectometer
How many jumps is it from "milli-" to "hecto-"? Five, to the left. So I move the decimal point five places to the left, filling in the empty spots after the decimal point with zeroes:
Density - Explained by Group 8 Co-editor: Joseph Geraghty Members: Matthew Moschella, Alex Ortiz
Section 3.4
I. Determining Density
Which is heavier, a pound of lead or a pound of feathers?
-pound of lead is -it would take a much larger volume of feathers to equal the mass of a given volume of lead
A. Density 1. the ratio of the mass of an object to its volume 2. It’s the important relationship between the objects mass and its volume * Formula is Density = Mass/Volume
When mass is measured in grams, and volume is measured in cubic centimeters, density has grams per cubic centimeter
Density is an intensive property that depends only on the composition of a substance, not in the size of the sample
Editor- Sejal Batra
What is Chemistry? - Explained by Group 1
Co-editor: Nathaniel Gullishaw
Members: Michael Clarke
Section 1.1
Matter is anything that has mass and occupies space. It can be visible or invisible.
Chemistry is the study of the composition of matter and the changes that matter undergoes. Chemistry applies to all aspects of life and most natural events because all living and nonliving things are made of matter.
Areas of Study
The scope of chemistry is vast, and there are traditionally 5 areas of study. These are
Pure and Applied Chemistry
Pure Chemistry is the study of chemistry for the sake of knowledge.Applied Chemistry is chemistry with a specific goal in mind. Sometimes, applied chemistry and pure chemistry can link to unexpectedly form an application.
Such examples are:
Nylon
Aspirin
Technology
Technology is how society provides its members with things needed or desired.
Why Study Chemistry?
Chemistry can impact all aspects of your life. Chemistry can be useful in explaining the natural world, preparing people for career opportunities, and producing informed citizens.
Explaining the Natural World
Chemistry can help you understand how things work. For example, chemistry can explain numerous aspects of food preparation.
Preparing For a Career
Being a chemist can be rewarding. Many careers involve chemistry, even though they do not necessarily include the word "chemist" in their title. People such as firefighters, reporters, and photographers all use chemistry at work.
Being an Informed Citizen
Industry, private foundations, and the federal government provide funds for research involving science. Many areas of research sometimes compete for funds. Some argue in favor of using funds for space exploration through programs such as NASA, while others support causes such as cancer research. Citizens will need to make choices that will determine the future development of technology. You may make decisions through elected representatives, at public hearings, or through petitions. Your knowledge of chemistry can help you make an informed decision and take appropriate action.
Chemistry Far and Wide - Explained by Group 2
Co-editor: Christopher Delude
Members: Kendall Lavin-Parsons
Section 1.2
Chemists try to design new materials to better fit specific needs of people. They often find inspiration for new designs in nature. They look at both the worlds of:
Macroscopic-the world of objects that are large enough to see with the naked eye (no help from microscopes, magnifying devices, etc)
Microscopic- the view of objects only able to be seen under magnification
With the population growth and increase in industrialization, the need for energy is much higher. Chemists play an important role in finding ways to conserve, store, and produce energy.
Conservation
Insulation is the most common form of conservation of energy. It maximizes the use of our heating and cooling that we use in daily situations (r
Production
Burning fossil fuels such as coal, petroleum, and natural gas is our major source of energy. Fossil fuels are a limited recourse, and chemists are trying to find energy sources that can be created easily. One plausible alternative is biodiesel. Biodiesel is energy made from plants, such as soy beans. Biodiesel is also better than fossil fuels (not only because it is renewable), but also because when used it does not release harmful gas for the environment. Storage
The most common storage for energy is in batteries. Various sizes, shapes, and functions are available for them (including rechargeable) to fit the needs of differing functions.
<http://www.foxnews.com/story/0,2933,516738,00.html>
Biotechnology has been the most important result from chemistry. It applies science to the production ofbiological products. It supplies new medicines, equipment, and technology for doctors to use to treat their patients.
Medicines
There are over 2,000 prescription drugs used to treat a variety of conditions. There are many other “over the counter” drugs such as aspirin or antacids which do not require prescriptions. Chemists work with biologists and doctors to help create these new medicines.
Materials
Chemists can create new materials to replace parts of the body which are not functioning. Plastic tubes can replace diseased arteries. Artificial knees and hips can replace worn out joints which cause a patient pain.
Agriculture
The worlds population is increasing - while the amount of space available to grow crops is decreasing, there fore we all must ensure to make this space as productive as possible.
Productivity
- One method of measuring productivity is is to see how much edible food is grown per a unit of land.
- Factors that decrease productivity; bad soil, lack of water, weeds, plant diseases, pests.
- Chemists can help increase productivity by testing the soil and using biochemistry to develop plants best capable of growing in bad weather.
- Chemists help to conserve water also.
Crop Protection- Instead of using non specific chemicals that were actually hurting the crops they now use chemicals that are specifically tested to only kill the bad pests.
- Some chemicals that are produced by insects can be used and manipulated to get rid pf bad insects.
- EX: female insects release a cchemical used to attract male insects and this chemical is proven to reduse pinworms.
Enviornment- Technology has some bad consequences including pollutants - material found in air, water, or soil that is harmful to humans and other organisms
Identify Pollutants- Lead is a pollutant.
- In the Roman empire lead was used in the pipes to store water and wine which might have lead to brain damage and ultimately the fall of the empire.
- It wasnt until after the mid 1900s that lead was stopped being used in common and dangerous products because studies taken in 1971 showed that even a very low level of lead in human blood is dangerous especially to young children.
Prevent Pollution- Use of lead in house paint was banned in 1978.
- Use of lead in gasoline and public water supply systems was banned in 1986.
- Prevention methods include; testing childrens blood, rules on house sales to families with children, and public awareness about how dangerous lead is.
The UniverseThinking like a Scientist - Explained by Group 3
Co-editor: Sean Doherty
Members: Monika Maczuga
Abby Williams
Section 1.3
Alchemy
- The word chemistry derives from the word alchemy
- Alchemy flourished in China and India as early as 400 B.C. Eventually, the Arabs brought the study to Spain. From there, it spread through Europe like wildfire.- Alchemy has a practical side and a mystical side (the best of both worlds)
Practical Alchemy primarily focuses on developing techniques for working with metals, glass, dyes, etc.
Mystical Alchemy focuses on concepts such as perfection.
Example: Since gold was valued as a perfect metal, alchemists were always seaching for ways to transform other less illustrious metals, such as lead, into gold. Outcome: None successfully completed the goal of a "new gold."
- Alchemists were also brilliant crafters of tools and techniques for working with various chemicas. We can thank them for allowing us to seperate and purify chemicals.
Examples of tools we use today: flasks, tongs, funnels, and the mortar (bowl shaped) and the pistle which is used as a grinder.
An Experiemental Approach to Science
- 1500s in Europe = shift from alchemy to science.
- 1600s in Britain = flourishing sciences under its supporter, King Charles II.
Royal Society of London for the Promotion of Natural Knowledge:
1. Scientists met to discuss scientific topics and conduct experiments.
2. The goal was to encourage and promote scientists to base their conclusions about the natural world on experimental evidence, not on philosophical debates.
Antoine Lavoisier!!!
- Late 1700s = his famous works took shape (France).
- Eventually, his brilliance would help transform chemistry from a science of observation to the science of measurment it is today.
Accomplishments:
1. Lavoisier developed an ingeniuos balance which could measure mass to the nearest 0.0005 gram.
2. Settled a long standing debate on how materials burn (oxygen).
~ During his time, the idea excepted was that materials burn because they contain phlogiston, which is released into the air as a material burns.
~ However, scientists had to ignore the fact that metals can gain mass as they burn. Lavoisier knew that there were two main gases in the air- oxygen and nitrogen.
~ He was able to successfully prove that oxygen must be present for a material to burn
Maria Anne was Lavoisier's wife and valuable aid. She was artistic allowing for her to make drawings of his experiments and translated scientific papers from English.
Execution:
- Lavoisier was a member of a despised royal taxation commission at the time of the French Revolution.
- He took the position to finance his scientific work. PROBLEM!
- Although he was dedicated to improving the lives of the common people, his association with bitter taxation made him a prime target.
- In 1794, he was arrested, found guilty, and beheaded.
The Scientific Method
- Scientific tool used for solving problems with a logical, systematic approach. -The method used steps
that include making observations, testing hypotheses, and developing theories.
-These tests usually contain variable factors which can change the results of the test.
- Manipulated variables are changed to alter the results.
- Responding Variables are observed during the test.
- The outcomes of these hypotheses experiments result in theories, or well tested result
that stays the same for a broad set of observations.
-Theories are then developed into laws, which are proven statements.
Collaboration and communication
- The use of team work to utilize the skill sets of each person working.
-Collaboration- The sharing of results or ideas with other scientists to gain more insight. - Can also result in conflict
with amount of workload to credit
-Communication- The use of technology to communicate results and ideas to others. (Internet!)
Problem Solving in Chemistry - Explained by Group 4
Co-editor: Andrew Whalen
Members: Katie Manis, Freddy Dwyer
Section 1.4
Skills Used in Solving Problems
-Problem solving is a skill used by people every day
- Decisions are made using problem solving skills
For example: You are in a supermarket and need to purchase an item. Problem solving and decision making come into play when you choose between a 1 and 2 liter bottle. Sometimes you must decide whether or not to buy a certain item based on ingredients that are in it. You may need to avoid certain ingredients due to an allergy you or a family member posseses. These are examples of problem solving that are used every day.
-The skills used to solve a word problem in chemistry are not much different from the scenario listed above.
*EFFECTIVE PROBLEM SOLVING ALWAYS INVOLVES DEVELOPING A PLAN AND THEN IMPLEMENTING THAT PLAN*
Solving Conceptual problems:
- To solve a conceptual problem you need to identify what is known and what is unknown.
-you need to make a plan for getting from the known to the unknown.- The three step problem solving approach is modified for conceptual problems.
- The steps for solving a conceptional problem are analyze and solve.
-when analyzing you identify the relevant concepts.-when solving the problem you apply concepts to the situation.
Measurement and their Uncertainty - Explained by Group 5
Co-editor: Andrew Humphrey
Members: Matthew McKeon, Lindsey Trafford
Section 3.1
Using and Expressing Measurement
Accuracy, Precision, and Error
Accuracy and Precision
- Accuracy is a measure of how close a measurement comes to the actual or true value of whatever is measured.
- Precision is a measure of how close a series of measurements are to one another.
- To evaluate the accuracy of a measurement, the measured value must be compared to the correct value. To evaluate the precision of a measurement of a measurement, you must compare the values of two or more repeated measurements.
Determining ErrorSignificant figures in measurements
- Significant figures in a measurement includes all of the digits that are already known and the last digit which is estimated.
- Calculated numbers often depend on the number of significant figures in a value used in a calculation.
- because calculated numbers depend so much on the significant figures the correct number of significant figuresmust always be reported.- The instruments used for measurement differ in significant figures and the amount of exact information they can provide.
- the calculations may all depend on the calibration of the instrument.Rules for determining whether a digit in a measurement is a significant figure:
- Every number that is not zero is assumed to be a significant figure (e.g. 24.7meters, 0.734 meter, and 714 meter).
- When a zero appears between two non-zero digits it is a significant figure (e.g. 7003meter, 40.79 meter, and 1.503 meter).
- Zeros in front of non-zero digits (significant figures) are not significant figures. they can be eliminated by using scientific notation (e.g. 0.0071 meter, 0.42 meter, and 0.000099).
- Zeros to the left of non-zero digits are significant figures (e.g. 43.00meters, 1.010 meters, and 9.000 meters).
- Zeros on the left of a decimal point but to the rightmost of the numbers are not significant figures. they can be put into scientific notation( e.g. 300 meters, 7000meters, and 27, 210 meters).
- there are 2 situations in which there is an unlimited number of significant figures. one involves counting and the other includes exactly defined quantities like those within a system of measurement. (e.g. counting 23 people in a class, or 60 min=1 hr, or 100 cm= 1 m)
Significant figures in calculations- When calculating significant figures the solution cannot be more precise than the least precise measurement in the calculation. the calculation must be rounded to make it consistant with the measurements in which it was calculated. (e.g. 7.7 meters by 5.4 meters equals 41.58 meters but the answer can only consist of two significant figures to match the calculated measurements 41.58 meters must be rounded to 42 m2).
Addition and subtractionThe Internal System of Units - Explained by Group 6
Co-editor: Lauren Rossi
Members: Patrick Hodge, Kevin Petterson.
Section 3.2
Measuring with SI units
international system of units- a revised version of the metric system. It was adopted in 1960. The five base units used by chemists are meter, kilogram, kelvin, second, and mole.
Units and Quantities
- Units of Length
- size is an important property of matter
- meter-the basic length or linear measure. All measurements can be measured in meters.
- milli- prefix that means 1/1000. millimeter= 1/1000 of a meter
- kilo- prefix that mean 1000. kilometer= 1000 meters
- Common metric units of length- centimeter, meter, and kilometer.
Units of Volume:Metric Units of Volume
Units of Mass:
Metric Units of Mass
Conversion Problems - Explained by Group 7
Co-editor: Emily Mills
Members: Kelsey Persechini, Emily Healy
Section 3.3
Conversion Factors
A quantity of the same amount or length can usually be expressed or measured in several different ways:
1 dollar = 4 quarters = 10 dimes = 20 nickels = 100 pennies OR
1 meter = 10 decimeters = 100 centimeters = 1000 millimeters
A conversion factor is a ratio of equivalent measurements.
Example ratio: 100cm / 1m and 1m / 100cm
Smaller number --> 1 m <-- larger unit
Larger number --> 100 cm <-- smaller unit
Measurement of the numerator = Measurement of the denominator
Conversion factors are useful in solving a problem that a given given measurement must be expressed in another unit.
When a measurement is multiplied by a conversion factor, the numerical value is generally changed, but the actual size of the quantity measured remains the same.
In other words, even though the numbers in the measurement are different, both of the measurements represent the same mass.
Converting Between Units
- In chemistry you must express measurement using a different unit than what is given or given in the first place
- Converting between metric units is easy to remember
- kilo- hecto- deka- [unit] deci- centi- milli-
- one memory trick Is “King Henry Doesn't [Usually] Drink Chocolate Milk”
- Between every unit is 10^1 with every place it goes up on exponent point 1 kilometer = 10 hectometers = 100 dekameters = 1000 meters = 10 000 decimeters = 100 000 centimeters = 1 000 000 millimeters
- If the unit is a gram that the different between a kilogram and a decigram is 104
- 1 milliliter = 0.1 centiliters = 0.01 deciliters = 0.001 liters = 0.000 1 dekaliters
- If you are going up of left of the units than you divide and if you are going down or right you multiply
- Example
- Express 750 decigrams in gram
- Mass= 750dg
- 1g= 10dg so 750/10 =?
- 750/10=75
- 750 decigram= 75 gram
- another way to think of it is
If you are going from a kilometer to a centimeter0.000 01 hectoliters
0.000 001 kiloliters
So I move the decimal point five places to the right, filling in the extra space with zeroes:
12.54 km = 1 254 000 cm
- How many jumps is it from "milli-" to "hecto-"? Five, to the left.
Then my answer is:457 mL = 0.00457 hLSo I move the decimal point five places to the left, filling in the empty spots after the decimal point with zeroes:
http://www.purplemath.com/modules/metric.htm
sometimes you have to convert ratio it is as easy as converting units there is just a few more steps
If you want to convert 7.21g/cm3 into ?kg/m3
you solve this by doing (7.21g /1 cm3 ) X (1kg / 1000 g3) X (100000cm3/1m3)
then the grams cancel each other out and the cm3 cancel each other out and you are left with 7.21 X 1000kg/m3
so your answer is 7210 kg/m3
DIMENSIONAL ANALYSIS
dimensional analysis is a way to analyze and solve problems using the units or dimensions of the measurments.
Dimensional analysis is routinely used to check the plausibility of derived equations and computations.
http://www.youtube.com/watch?v=aZ3J60GYo6U
Density - Explained by Group 8
Co-editor: Joseph Geraghty
Members: Matthew Moschella, Alex Ortiz
Section 3.4
I. Determining Density
- Which is heavier, a pound of lead or a pound of feathers?
-pound of lead is-it would take a much larger volume of feathers to equal the mass of a given volume of lead
A. Density
1. the ratio of the mass of an object to its volume
2. It’s the important relationship between the objects mass and its volume
* Formula is Density = Mass/Volume